“The oldest set of federally placed monuments in the United States are strewn along busy streets, hidden in dense forests, lying unassumingly in residential front yards and church parking lots,” he explains. “Many are fortified by small iron fences, and one resides in the sea wall of a Potomac River lighthouse. Lining the current and former boundaries of Washington, D.C., these are the boundary stones of our nation’s capital.”

Nearly all of them—36 out of 40—can still be found today, although they are not necessarily easy to identify. “Some stones legibly maintain their original inscriptions marking the ‘Jurisdiction of the United States,’ while others have been severely eroded or sunk into the ground so as to now resemble ordinary, naturally-occurring stones.” They have been hit by cars and obscured by poison ivy.

The question of who owns the stones—and thus has responsibility for preserving them—is complex, as the Washington Post pointed out back in 2014. “Those that sit on the D.C./Maryland line were deemed the property of the D.C. Department of Transportation. ‘But on the Virginia side, if you own the land, you own the stone,’ [Stephen Powers of boundarystones.org] says.”

Novelist Jeremy Bushnell joked on Twitter that, “if anyone knows the incantations that correctly activate these, now would be a good time to utter them,” and, indeed, there is something vaguely magical—in a Nicolas Cage sort of way—in this vision of the nation’s capital encaged by a protective geometry of aging obelisks. Whether “activating” them would have beneficial or nefarious ends, I suppose, is something that remains to be seen.

In other cases, it’s just the pure bulk of masonry and its interaction with sunlight that remains so visually compelling, where looking at the city almost meant looking at a geological formation, an artificial mountain chain that you knew was filled with rooms and hallways waiting to be explored.

Finally, these old, looming roof profiles from buildings in Germany are spectacular.

Architects and engineers today should spend more time thinking about roofs, as spaces that can be inhabited, not merely as minimal surfaces used for no other purpose than to cover another space.

Roofs should be labyrinths you can walk through and get lost within. Roofs should have dimension; they should have windows and rooms. They should be spaces in their own right, not just lines where other spaces end.

While going through a bunch of old photos of Los Angeles on the Library of Congress website for a project I’m doing at USC this year, I was amazed by these interior shots of the F. E. Weymouth Filtration Plant at 700 North Moreno Avenue in L.A.

Despite being designed for the administration of an urban water-processing site, the interiors seem to play with some strange, Blade Runner-like variation on Byzantine modernism, where federalist detailing meets a hydrological Babylon.

As the open plan interior of a contemporary home, this place would almost undoubtedly show up on every design website today—imagine a better railing on the central staircase, a galley kitchen on one side, a bed lit by retro-styled fluorescent tubes at the far end, some bold moments of color—but it’s just a piece of everyday municipal infrastructure.

In any case, continuing the vaguely sci-fi feel, there is even a tiled fountain—a Mediterranean concession to the building’s role in water filtration—on one wall, emphasized by these amazing lighting features, yet it looks more like a film set, both ancient and futuristic.

Alas, I’m not a huge fan of the exterior, although it is, in fact, a fairly amazing example of municipal design gone more sacred than profane. But an equally streamlined modernism in keeping with those interiors would have made this place totally otherworldly.

Finally, the marbled lobbies continue the surreal mix-up of styles, eras, and materials with something that could perhaps be described as Aztec corporatism with its huge graphic seal and other geometric motifs.